It's a ripening mystery: Who's stealing the wine grapes of Germany?
Thieves raiding lucrative southern German vineyards have made off with a minor fortune in fruit over more than a dozen forays under the cover of darkness.
Vintners have increased their vigilance, posted guards and sought help from the police, but so far, the thieves have made off without a trace.
"They picked off more than 2,500 kilograms of my best red grapes," said Stephan Attmann, who runs a vineyard near Deidesheim in southwestern Germany.
"It hurts, not just financially, but also emotionally," Attmann said. "We had spent weeks preparing the vines, getting rid of all the sour grapes, and then they came one night and stole everything."
Attmann estimates his losses so far this season at some euro100,000 ($137,700) _ more than 3,000 bottles of high-class Pinot Noir selling for euro32 a bottle. He said he did not have any kind of insurance that covered the losses.
Hundreds of thousands of euros worth of grapes have been stolen across the wine region _ and winemakers fear the worst may not be over.
While most of this year's grapes have been picked, vintners are still waiting for the first autumn frost to bring the deep chill needed before they can reap their lucrative ice wine grapes.
Sweet high-class ice wines are even more expensive than regular wines, making the remaining grapes especially valuable _ and a likely prime target for the thieves.
"The vintners don't have a large amount of those grapes, but you can be sure that they are watching the ice wine grapes like hawks until they can harvest them," said Rainer Koeller, a Heilbronn police officer who has been involved in the investigation of the thefts.
The region was already suffering this year after a late frost in May wiped out a lot of grapes _ and there's speculation the thieves could be other vintners, seeking to make up for those losses.
Attmann, whose wine estate Weingut von Winning is known to produce some of the best wines in the Pfalz region, is convinced that professional winemakers are at work. He notes that the thieves who stole his grapes used a harvesting machine at night, taking them just a few days before he was going to pick them himself.
"Often vintners pick their grapes at night, so it doesn't raise particular attention if people are working in the wine hills in the dark," he said. "But if they come with a harvesting machine, they definitely know what they're doing."
The vintners in the rolling hills surrounding the city of Heilbronn, 100 kilometers (60 miles) east of Deidesheim, have been hit more than 10 times this year, and are also convinced pros are behind the thefts.
The thieves came at night, and targeted primarily white Riesling, Trollinger or Grauburgunder grapes.
"We were once called to a vineyard in the early morning hours because witnesses saw two people moving with flashlights between the vines," said Koeller, the Heilbronn investigator. "But by the time we arrived, the suspects were gone, the vines were empty and as of today we still don't have a hot lead."
In the Heilbronn area, the thieves have always hand-picked the grapes and no area has been safe from the robberies.
"This is really a catastrophe for us," said vintner Albrecht Loehl of Flein, who lost 2,500 kilograms (5,500 pounds) of white Trollinger grapes. "We were already hard hit by the late frost in May that destroyed many of our grapes."
He said the thieves seemed to know their way around a vineyard even though they didn't use harvesting machines.
"The thieves picked off my ripe grapes and avoided the sour ones," he said, still in disbelief. "They emptied 25 vine rows, each row 53 meters (yards) long."
Ernst Buescher, a spokesman for the German Wine Institute, said many vineyards may face bankruptcy this year after losing all of their fruit to the May frost. What makes it worse _ the grapes that survived have been particularly good, producing some of the best wine in years.
The combination might have turned some to theft "out of desperation," he said. "Not that those motives would justify anything."
"It's a great harvest this year, a precious wine, very harmonic due to the long maturing time and the golden autumn weather," Buescher said, adding that whoever made off with the grapes will be able to sell good wines for a good price.
Some of Germany's vineyards date to the Middle Ages, and it is not the first time thieves have targeted them, though nobody can remember a year like this one.
In the past, vintners would simply shut down all roads leading to the wine hills during harvest time and keep outsiders away.
But the growing number of tourists who come to taste the new wines, or simply enjoy hiking the hills in autumn when the wine leaves turn bright red and yellow, led communities in the region to abolish the ban in the early 1990s.
The tourism industry is too important to consider reinstituting the ban. But since the region has opened up, some towns and cities, like Stuttgart and Fellbach, have sent guards to the wine hills.
But most wine estates, which are mostly still family-run, simply cannot afford to do that and the fields are too vast to be effectively protected by individuals.
"When I look out of my window, I can see vineyards all the way to the horizon," said Heilbronn police's Koeller.
"There's no way one can guard all of this, especially at night."